Messages in this thread | | | Date | Mon, 7 Feb 2022 16:36:07 +0100 | From | Frederic Weisbecker <> | Subject | Re: [patch v11 09/13] task isolation: add preempt notifier to sync per-CPU vmstat dirty info to thread info |
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On Fri, Feb 04, 2022 at 02:35:46PM -0300, Marcelo Tosatti wrote: > If a thread has task isolation activated, is preempted by thread B, > which marks vmstat information dirty, and is preempted back in, > one might return to userspace with vmstat dirty information on the > CPU in question. > > To address this problem, add a preempt notifier that transfers vmstat dirty > information to TIF_TASK_ISOL thread flag.
Ah ok that answers my previous question :)
> Index: linux-2.6/mm/vmstat.c > =================================================================== > --- linux-2.6.orig/mm/vmstat.c > +++ linux-2.6/mm/vmstat.c > @@ -353,6 +353,13 @@ void init_sync_vmstat(void) > set_thread_flag(TIF_TASK_ISOL); > } > EXPORT_SYMBOL_GPL(vmstat_dirty); > + > +void vmstat_dirty_to_thread_flag(void) > +{ > + if (raw_cpu_read(vmstat_dirty) == true)
__this_cpu_read()?
> + set_thread_flag(TIF_TASK_ISOL); > +} > +EXPORT_SYMBOL_GPL(vmstat_dirty_to_thread_flag); > #else > static inline void mark_vmstat_dirty(void) > { > >
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